Grendel attacks because he is evil (spawn of Cain) and hates the happiness and noise of the men at the hall. He attacks killing 30 men, and then goes back the next night for more. The only way men can stay alive is to leave the hall.
Consequently, how does Hrothgar come to know Beowulf's father?
Ecgtheow, Beowulf's father, once found himself in a blood-feud with the tribe called the Wulfings because he had killed a man named Heatholaf. Ecgtheow sought refuge with King Hrothgar of the Danes, who eventually "healed the feud by paying" (470)—that is, he made reparations to the Wulfings on Ecgtheow's behalf.
What is the relationship between Hrothgar and Grendel?
The relationship between Hrothgar and Grendel, in Beowulf, is one of utter hatred. Hrothgar has built a mead hall, Heorot, to celebrate God and his power. Grendel, on the other hand, hates God. His anger stems from the fact that he is in exile given the sins of his ancestors.
How is Hrothgar described in Beowulf?
Hrothgar is the king of the Spear-Danes when Beowulf arrives in their land, ready to fight the demon Grendel. Many years earlier, Hrothgar paid money to the Wulfings to resolve a blood feud they had with Ecgtheow, Beowulf's father.